@colshacol
the 'provides' option is used to mark the package as a replacement for another package. If some application has mariadb like dependency (any package in the official repository cannot have a dependency on mysql), this package can be a candidate for replacement. Obviously the two packages are different in many ways.

@Muflone Forgive my novice, I have never used MySQL nor MariaDB. But, I saw that you said that this has nothing to do with MariaDB, yet it says "provides: mariadb" above, and upon checking mysql --version, I get "Ver 15.1 Distrib 10.1.14-MariaDB, for Linux (x86_64) using readline 5.1".

I am not complaining. I do not even know the difference! I am just curious as to why you say it is not related to Maria at all.

I hope it will be cleared that your AUR helper (the program you're using to download the packages) is doing mess.
The package mysql is in the AUR while the package mariadb is in the official Arch Linux repository. Your AUR helper is downloading mariadb from the repository instead of the AUR package mysql.

Just download the package from the AUR, like kerberizer pointed and be happy with mysql.